Study on Episodes and Identification of the Interaction of Geofluids with Sandstones in Dongying Halfgraben, Shengli Oil Field

Key words: 
• geofluid /
• sandstone /
• interaction /
• identification mark /
• Dongying halfgraben

Abstract: The reservoir sandstones in Dongying Dongying Halfgraben, Shengli Oil Field have undergone four episodes of interaction of geofluids with sandstone. Dissolution, cementation and microvein filling are the major diagenesis under fluid flows. Normally, the dissolution enhances the reservoir quality, while the cementation damages the reservoir quality. But some earlier carbonate cements like coarse ankerite support the skeleton grains and prevent the reservoir sandstones from porous “collapse”. Based on the observation under microscope and probe analyses, four episodes Ⅰ, Ⅱ, Ⅲ and Ⅳ of geofluid activities have been identified for the study area